Dry Ice Blasting
Dry
ice blasting is a relatively new cleaning process using solid CO2
pellets (known as dry ice). It is primarily used for industrial
use in a variety of applications. The pellets sublimate (convert
directly from a solid blast pellet to a vapor (CO2) leaving no residue.
The CO2 blasting process is superior to blasting with sand or
glass bead and other types of cleaning methods for numerous reasons
(see Dry Ice Blasting Comparison Chart below).
Today,
the dry ice cleaning method is quickly becoming favored for environmental
as well as production reasons. Because of tremendous environmental
regulations, industry has needed to minimize wastes. Also, there
is a growing consciousness that many are placing now on the global
environmental impact of their production practices. However, these
benefits are accentuated due to the tremendous performance gains
through dry ice blasting -- little or no production downtime, quality
of clean and minimized damaged to equipment.
What Is Dry Ice
Dry
ice pellets are made by taking liquid carbon dioxide (CO2) from a
pressurized storage tank and expanding it at ambient pressure to produce
snow. The snow is then compressed through a die to make hard pellets.
What Is Dry Ice Blasting
It
is a process in which dry ice particles are propelled to supersonic
speed, to impact and clean a surface. The particles are accelerated
by compressed air, just as with other blasting systems.
The
micro-thermal shock (caused by the dry ice temperature of -79º C),
the kinetic energy of dry ice pellets and the air pressure break the
bond between the coating and the substrate. It pops off the coating
from inside out and the air stream removes it from the surface.
Industries
can utilize the CO2 blasting method through equipment
that fires the pellets through a blasting gun. Upon impact the dry ice
sublimates (vaporizes). There are many major benefits to this cleaning process.
To read of them in detail, see our Dry Ice Blasting Benefits page.
Dry Ice Blasting Compared to Traditional Methods
The
following two charts give a helpful perspective of how CO2 blasting
compares with the traditional cleaning methods -- sand, blasting,
solvents, and others:.
|
Dry Ice Blast Cleaning Comparison Chart |
| Blasting
Cleaning Technique |
Waste for Disposal |
Abrasive |
Toxic |
Electrically Conductive |
Performance Comparison |
| Dry
Ice |
No |
No |
No |
No |
Excellent |
|
Sand |
Yes |
Yes |
No* |
No |
OK |
|
Glass Beads |
Yes |
Yes |
No* |
No |
OK |
|
Walnut Shells |
Yes |
Yes |
No* |
No |
Limited |
|
Steam |
No |
No |
No |
Yes |
Poor |
|
Solvents |
Yes |
No |
Yes |
Yes |
Limited |
|
* Each
of these blast cleaning materials becomes contaminated upon
contact if used to clean hazardous objects. When that happens, these
materials are then classified as toxic waste requiring safe disposal. |
| Cleaning
Method Comparison |
| Issue |
Traditional |
Dry
Ice Blasting |
| Equipment
Downtime |
Cleaned
in dedicated cleaning area; Disassembly/reassembly; Drying time required
|
Equipment
can be cleaned in place; Dry process - equipment restart immediately
after cleaning |
| Hazardous Waste |
Cleaner becomes and treated as a secondary contaminant |
No
additional contaminant; Dry ice sublimates with contact with targeted
surface |
| Labor
Hours |
Intensive
hand scrubbing; Lengthy cleanings; Follow-up cleaning-up can be lengthy |
Dramatically
reduced - often completed in a quarter of time or better |
| Quality of Cleaning |
Poor to average |
Excellent |
| Potential Equipment Damage |
Grit
abrasions; Grit contamination; Movement of equipment to and from cleaning
area |
No
equipment damage; Preventive maintenance very realistic as labor hours
are significantly less |
| Safety |
Health
threats from solvents; Water-based cleaning pose hazards around electrical
equipment; Threats to environment |
Standard
safety precautions; Dry process - safe around electrical equipment |
| Cost |
Cleaner
becomes additional hazardous waste; expensive solvents; Additional
labor |
Minimal - cost of dry ice |
|
